spring boot使用拦截器(以session校验为例)

这里我以session登录校验为例写了一个拦截器的例子

1.先写一个通过用户名密码登录的小栗子(用户名、密码都是root)

@Controller
@RestController
public class LoginController {

    @RequestMapping("login")
    public String login(String name,String pwd,HttpServletRequest request) {
        HttpSession session = request.getSession();

        if(name.equals("root")&&pwd.equals("root")) {
            User user = new User();
            user.setName(name);
            session.setAttribute("user",user);
            return "登录成功";
        } else {
            return "用户名或密码错误!";
        }
    }
}

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2.写登录校验的过滤器

新建一个SessionInterceptor 实现（implements）HandlerInterceptor接口,并重写其中的方法

public class SessionInterceptor implements HandlerInterceptor {

    @Override
    public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception {
        System.out.println("开始请求地址拦截");
        HttpSession session = request.getSession(false);

        if (session != null && session.getAttribute("user") != null) {
            return true;
        } else {
            PrintWriter printWriter = response.getWriter();
            printWriter.write("{code:0,message:\"not login!\"}");
            return false;
        }
    }

    @Override
    public void postHandle(HttpServletRequest request, HttpServletResponse response, Object handler, ModelAndView modelAndView) throws Exception {
        System.out.println("返回视图或String之前的处理");
    }

    @Override
    public void afterCompletion(HttpServletRequest request, HttpServletResponse response, Object handler, Exception ex) throws Exception {
        System.out.println("返回视图或String之前的处理");
    }
}

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3.完成拦截器的注册

@Configuration
public class WebAppConfig extends WebMvcConfigurerAdapter {

    /**
     * 注册 拦截器
     */
    @Override
    public void addInterceptors(InterceptorRegistry registry) {
        // 设置拦截的路径、不拦截的路径、优先级等等
        registry.addInterceptor(new SessionInterceptor()).addPathPatterns("/*").excludePathPatterns("/login");
    }
}

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4.测试

(1)首先写一个代表其他资源的控制器OtherController

@RestController
public class OtherController {
    @RequestMapping("other")
    public String login(String name,String pwd,HttpServletRequest request) {

        return "other!";
    }
}

(2)直接访问OtherController

拦截器会拦截下这个请求
(3)登录后再访问OtherController

登录后再访问其他资源,便可以直接访问

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5.源码

git源码地址